Despite not having a fan, the G9 II performs well in terms of overheating. This is because smaller sensors produce less heat. The previous model, the S5 II, could only record for 30 minutes in 6K mode, but the G9 II has no such limitations. To test its performance under extreme conditions, the camera was placed in a non-air-conditioned space with an ambient temperature of around 80 degrees Fahrenheit, and various video modes were tested.

In most common resolutions and framerates, the G9 II handles the workload without any issues. It can keep running until the battery dies, which is around 90 minutes with a full charge. Only at the highest resolutions and framerates does overheating become a possibility. After continuous recording, the grip and viewfinder of the camera become uncomfortably hot, and eventually, the camera shuts down to cool down.

The G9 II managed to run for 54 minutes at the maximum 5.8k resolution before overheating. It also performed well at 4K 60, running for a respectable 50 minutes. However, in the case of 4K 120, the camera could only sustain recording for 19 minutes before shutting down. However, in real-world scenarios, 120 FPS is rarely needed for more than a few seconds at a time, so this limitation may not be a significant issue. If you require better cooling, consider upgrading to the GH6 model.